Viability of Pony Stallion Semen in Different Temperature and Dilution

ABSTRACT

Background: Artificial insemination and transport of cooled semen has been routinely used in equine industry in the past 20 years. However, more investigations are needed regarding the methods for long time storage in pony stallion semen. The effect of dilution and cooling temperature on pH, sperm motility, membrane integrity and mitochondrial activity were investigated before and after cooling of stallion semen.Materials, Methods & Results: Two ejaculates each from nine Brazilian ponies were diluted in a nonbuffered powder milk extender cooled at 5C or 15C for 48 h using three different dilutions (11, 12 or 13). Data were assessed by analysis of variance and the rate comparison was performed using the Duncan test. Samples diluted 11 at 5oC or 15C showed higher pH values (7.63 ± 0.34 e 7.57 ± 0.27) and lower progressive motility (10.3 ± 11.05, 17.08 ± 9.95). All samples cooled at 15C also showed lower incidence of morphologically altered spermatozoa (11 = 55.84%; 12 = 51.84%; 13 = 49.95%) [P 0.01]. Mitochondrial activity was higher on the 13 dilution (0.86 ± 0.19 nm) at 5C and on the 11 (0.89 ± 0.23 nm), 12 (0.93 ± 0.2 nm) and 13 (0.92 ± 0.2 nm) dilutions at 15C. Progressive motility was higher when semen was diluted 13 and cooled at 15C (42.22 ± 12.38; P 0.05). Considering mitochondrial activity, similar results were observed when different dil